I'm building a motorcycle intercom/music system. I need an in-line volume control for my passenger's headset/earbuds. Because she needs to adjust the volume with gloves on, the small manufactured in-line volume controls will not work. I am therefore installing a rotary pot with a knob that she can operate with her gloves on. I've searched and Googled to no avail to get an answer to this very basic question - I have both a 10K pot and a 100K pot (both dual gang, the 10K pot is probably higher quality). Which should I use? Thanks!!
If you must use one of the pots you already have, use the 10k. Otherwise, go with a 1k.
I cracked open the volume control on a cheap pair of headphones I have here and they were using a 1k. A 500 ohm would work fine as well but 500 ohm audio taper pots aren't terribly common.
Check out Mouser part number 313-2420F-1K. You might be able to find something similar if not identical at your local Rat Shack too.
se
I cracked open the volume control on a cheap pair of headphones I have here and they were using a 1k. A 500 ohm would work fine as well but 500 ohm audio taper pots aren't terribly common.
Check out Mouser part number 313-2420F-1K. You might be able to find something similar if not identical at your local Rat Shack too.
se
Thanks, Steve. So I can be more knowledgeable, I'd like to know the significance of using 1k versus 10k versus 100k. Thanks, again.
Output impedance.
As you rotate the pot, the output impedance changes. Ideally the worst case is when the pot is at the mid point of its resistance and the output impedance is 1/4 the end to end resistance of the pot.
So with a 10k pot, that would be 2.5k ohms and with a 100k pot, 25k ohms.
That can result in some rather significant changes in the headphone's frequency response. Also, it will result in a really weird volume taper.
With a 1k pot, you're looking at 250 ohms. Certainly not ideal, but an order of magnitude better than a 10k pot.
se
As you rotate the pot, the output impedance changes. Ideally the worst case is when the pot is at the mid point of its resistance and the output impedance is 1/4 the end to end resistance of the pot.
So with a 10k pot, that would be 2.5k ohms and with a 100k pot, 25k ohms.
That can result in some rather significant changes in the headphone's frequency response. Also, it will result in a really weird volume taper.
With a 1k pot, you're looking at 250 ohms. Certainly not ideal, but an order of magnitude better than a 10k pot.
se
OK. What you said makes perfect sense to me.I appreciate the explanation. If I can ask just one last question (I promise!): Given that, why would one ever use a higher (10k, 100k) pot? What would be the advantage?
Thanks again.
Thanks again.
I can't think of any advantage whatsoever using a 10k or 100k pot for attenuating a headphone output. Sure, if it's at the input of the amplifier, that's fine. But not when the headphone's going to be directly connected to the pot.
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